Endoscope with single step guiding apparatus

ABSTRACT

An endoscope with guiding apparatus is described herein. A steerable endoscope is described having an elongate body with a manually or selectively steerable distal portion, an automatically controlled portion, a flexible and passively manipulated proximal portion, and an externally controlled and manipulatable tracking rod or guide. The tracking rod or guide is positioned within a guide channel within the endoscope and slides relative to the endoscope. When the guide is in a flexible state, it can conform to a curve or path defined by the steerable distal portion and the automatically controlled portion. The guide can then be selectively rigidized to assume that curve or path. Once set, the endoscope can be advanced over the rigidized guide in a monorail or “piggy-back” fashion so that the flexible proximal portion follows the curve held by the guide until the endoscope reaches a next point of curvature within a body lumen.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 10/087,100 entitled “Endoscope with GuidingApparatus” filed Mar. 1, 2002, which is a continuation-in-part of U.S.patent application Ser. No. 09/969,927 entitled “Steerable SegmentedEndoscope and Method of Insertion” filed Oct. 2, 2001, which is acontinuation-in-part of U.S. patent application Ser. No. 09/790,204entitled “Steerable Endoscope and Improved Method of Insertion” filedFeb. 20, 2001, which claims the benefit of priority to U.S. ProvisionalPatent Application Serial No. 60/194,140 entitled the same and filedApr. 3, 2000, all of which are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to endoscopes andendoscopic procedures. More particularly, it relates to a method andapparatus to facilitate insertion of a flexible endoscope along atortuous path, such as for colonoscopic examination and treatment.

BACKGROUND OF THE INVENTION

[0003] An endoscope is a medical instrument for visualizing the interiorof a patient's body. Endoscopes can be used for a variety of differentdiagnostic and interventional procedures, including colonoscopy,bronchoscopy, thoracoscopy, laparoscopy and video endoscopy.

[0004] Colonoscopy is a medical procedure in which a flexible endoscope,or colonoscope, is inserted into a patient's colon for diagnosticexamination and/or surgical treatment of the colon. A standardcolonoscope is typically 135-185 cm in length and 12-19 mm in diameter,and includes a fiberoptic imaging bundle or a miniature camera locatedat the instrument's tip, illumination fibers, one or two instrumentchannels that may also be used for insufflation or irrigation, air andwater channels, and vacuum channels. The colonoscope is inserted via thepatient's anus and is advanced through the colon, allowing direct visualexamination of the colon, the ileocecal valve and portions of theterminal ileum.

[0005] Insertion of the colonoscope is complicated by the fact that thecolon represents a tortuous and convoluted path. Considerablemanipulation of the colonoscope is often necessary to advance thecolonoscope through the colon, making the procedure more difficult andtime consuming and adding to the potential for complications, such asintestinal perforation. Steerable colonoscopes have been devised tofacilitate selection of the correct path though the curves of the colon.However, as the colonoscope is inserted farther and farther into thecolon, it becomes more difficult to advance the colonoscope along theselected path. At each turn, the wall of the colon must maintain thecurve in the colonoscope. The colonoscope rubs against the mucosalsurface of the colon along the outside of each turn. Friction and slackin the colonoscope build up at each turn, making it more and moredifficult to advance, withdraw, and loop the colonoscope. In addition,the force against the wall of the colon increases with the buildup offriction. In cases of extreme tortuosity, it may become impossible toadvance the colonoscope all of the way through the colon.

[0006] Steerable endoscopes, catheters and insertion devices for medicalexamination or treatment of internal body structures are described inthe following U.S. patents, the disclosures of which are herebyincorporated by reference in their entirety: U.S. Pat. Nos. 4,543,090;4,753,223; 5,337,732; 5,337,733; 5,383,852; 5,487,757; 5,624,381;5,662,587; and 5,759,151.

SUMMARY OF THE INVENTION

[0007] Accordingly, an improved endoscopic apparatus is disclosed hereinfor the examination of a patient's colon, other internal bodilycavities, and any other spaces within the body with minimal impingementupon bodily cavities or upon the walls of the organs. The disclosedapparatus may also be employed for various surgical treatments of thoseregions, e.g., insufflation, drug delivery, biopsies, etc. A steerableendoscope having an elongate body with a manually or selectivelysteerable distal portion, an automatically controlled portion, which maybe optionally omitted from the device, a flexible and passivelymanipulated proximal portion, and an externally controlled andmanipulatable tracking rod or guide is described below. The tracking rodor guide may be slidably positioned within a guide channel or lumenwithin the endoscope or it may be externally positionable such that theguide and the endoscope may slide relative to one another along a railor channel located along an external surface of the endoscope.

[0008] In operation, the steerable distal portion of the endoscope maybe first advanced into a patient's rectum via the anus. The endoscopemay be simply advanced, either manually or automatically by a motor,until the first curvature is reached. At this point, the steerabledistal portion may be actively controlled by the physician or surgeon toattain an optimal curvature or shape for advancement of the endoscope.The optimal curvature or shape is considered to be the path whichpresents the least amount of contact or interference from the walls ofthe colon. In one variation, once the desired curvature has beendetermined, the endoscope may be advanced further into the colon suchthat the automatically controlled segments of controllable portionfollow the distal portion while transmitting the optimal curvature orshape proximally down the remaining segments of the controllableportion. The operation of the controllable segments will be described infurther detail below.

[0009] In one variation, the guide is shorter than the full length ofthe endoscope, e.g., approximately the length of the controllableportion, and this shortened guide can be preloaded through the proximalend of the endoscope or through the handle of the endoscope. Once theguide is inserted, it may be advanced distally through the endoscope tothe distal tip of the endoscope. As the user advances the endoscopedistally, the automatically controlled segments of the proximalcontrollable portion propagate the selected curves down the endoscope,and the guide, in its flexible state, passively conforms to the shape ofthe desired pathway. Once the endoscope has advanced to a desiredposition, e.g. to a depth less than the length of the controllableportion of the endoscope, the user can rigidize the guide and maintainit at that depth (or axial position). The endoscope can then be furtheradvanced relative to the rigidized guide, sliding over the rigid guideand along the selected pathway. Thus, the surgeon or physician onlyneeds to lock the guide in position once. If the controllable region ofthe endoscope and the guide are each at least half of the length of theendoscope, the entire endoscope can conform to a selected pathway inthis manner. It is also possible to reposition the guide easily byrelaxing and/or unlocking it from its rigidized axial position and thenmoving the guide into its new position.

[0010] In an alternative variation, once the steerable distal portionhas been steered or positioned for advancement, the guide may beadvanced distally in its flexible state along or within the endoscopeuntil it reaches a distal position, i.e., preferably some point distalof the flexible proximal portion. Regardless whether the optionalcontrollable portion is omitted or not from the device, the guide may beadvanced near or to the end of the distal portion. Once the guide hasbeen advanced, it may directly attain and conform to the curvature orshape defined by the steerable distal portion.

[0011] Preferably, the guide is advanced to the distal end of steerabledistal portion or, if the controllable portion is included in thedevice, the guide may be advanced to the distal end of the controllableportion, or to some point between the two portions. The guide may beadvanced to any distal position as long as a portion of guide attainsand conforms to the optimal curvature or shape. Prior to advancing theendoscope over the guide, the guide may be left in its flexible state orit may be optionally rigidized, as discussed further below. If left inits flexible state, the guide may possibly provide desirable columnstrength to the endoscope as it is advanced through the colon over theguide. It is preferable, however, that the guide is rigidized once ithas attained and conformed to the curvature. This allows the flexibleproximal portion, i.e., the passive portion, to remain flexible andlightweight in structure. As the position of the guide is preferablyrigidized and maintained, the endoscope may then be advanced over theguide in a monorail or “piggy-back” fashion so that the flexibleproximal portion follows the curve held by the guide until the endoscopereaches the next point of curvature.

[0012] In some variations, the process of alternately advancing theguide and the endoscope may be repeated to advance the entire endoscopethrough the colon while the guide may be alternatively rigidized andrelaxed while being advanced distally. While the endoscope is advancedthrough the colon, the physician or surgeon may stop the advancement toexamine various areas along the colon wall using, e.g., an imagingbundle located at the distal end of the endoscope. During suchexaminations, the guide may be temporarily withdrawn from the endoscopeto allow for the insertion of other tools through the guide channel ifthere is no separate channel defined within the endoscope for the guide.The guide may also be withdrawn through the instrument to any locationwithin the body of the endoscope. In other words, the guide may bewithdrawn partially or removed entirely from the endoscope at any time,if desired, because there are no constraints which may limit the travelof the guide through the body of the endoscope. After a procedure hasbeen completed on the colon wall, the tool may be withdrawn from theguide channel and the guide may be reintroduced into the endoscope sothat the endoscope may optionally be advanced once again into the colon.

[0013] A further variation on advancing the endoscope may use multipleguides which are alternately rigidized while being advanced distallyalong a path. Although multiple guides may be used, two guides arepreferably utilized. As the endoscopic device approaches a curvature, afirst guide may be advanced in a relaxed and flexible state towards thesteerable distal end of the device. While being advanced, the firstguide preferably conforms to the shape defined by the distal end and thefirst guide may be subsequently rigidized to maintain this shape. Thedevice may then be advanced further distally along the pathway whileriding over the rigidized first guide.

[0014] After the device has been advanced to its new position, a secondguide may also be advanced distally in its relaxed state through thedevice up to the distal end while the first guide is maintained in itsrigidized state. The second guide may then conform to the new shapedefined by the distal end of the device and become rigidized to maintainthis new shape. At this point, the first guide is also preferablymaintained in its rigid state until the distal end of the device hasbeen advanced further distally. The first guide may then be relaxed andadvanced while the rigidity of the second guide provides the strengthfor advancing the guide. This procedure may be repeated as necessary fornegotiating the pathway.

[0015] To withdraw the endoscope from within the colon, the procedureabove may be reversed such that the withdrawal minimally contacts thewalls of the colon. Alternatively, the guide may simply be removed fromthe endoscope while leaving the endoscope within the colon.Alternatively, the guide may be left inside the endoscope in the relaxedmode. The endoscope may then be simply withdrawn by pulling the proximalportion to remove the device. This method may rub or contact theendoscope upon the walls of the colon, but any impingement would beminimal.

[0016] The selectively steerable distal portion can be selectivelysteered or bent up to a full 180° bend in any direction. A fiberopticimaging bundle and one or more illumination fibers may extend throughthe body from the proximal portion to the distal portion. Theillumination fibers are preferably in communication with a light source,i.e., conventional light sources, which may be positioned at someexternal location, or other sources such as LEDs. Alternatively, theendoscope may be configured as a video endoscope with a miniaturizedvideo camera, such as a CCD camera, positioned at the distal portion ofthe endoscope body. The video camera may be used in combination with theillumination fibers. Optionally, the body of the endoscope may alsoinclude one or two access lumens that may optionally be used forinsufflation or irrigation, air and water channels, and vacuum channels,etc. Generally, the body of the endoscope is highly flexible so that itis able to bend around small diameter curves without buckling or kinkingwhile maintaining the various channels intact. The endoscope can be madein a variety of other sizes and configurations for other medical andindustrial applications.

[0017] In some variations the endoscope may optionally include a suctiondevice that can withdraw air or other gases, e.g. gases used forinsufflating the interior of a colon. In the example of insufflating acolon, the insufflated gas may be trapped within regions of the colondue to the sacculation and movement of the colon walls. To facilitateremoval of these gases, the suction device may be utilized to withdrawthese trapped gases as the endoscope is advanced or withdrawn throughthe colon.

[0018] The suction device may comprise a suction tube positioned withinthe endoscope and connected to a suction port defined along theendoscope outer surface at a location proximal of the distal tip. Thesuction port can apply suction at some distance from the tip of theendoscope so that the suction does not interfere with insufflation orother activities at the distal end of the endoscope. In one variation,the suction port is located in the distal half of the endoscope,approximately one-quarter down the length of the insertable portion ofthe endoscope, e.g., 40 to 50 cm from the steerable tip. Some variationsmay apply suction continuously, while others allow the user toselectively control application of the suction.

[0019] The optional controllable portion is composed of at least onesegment and preferably several segments which may be controllable via acomputer and/or controller located at a distance from the endoscope. Inone variation, approximately half of the length of the endoscope iscomprised of controllable segments. Each of the segments preferably havean actuator mechanically connecting adjacent segments to allow for thecontrolled motion of the segments in space. The actuators driving thesegments may include a variety of different types of mechanisms, e.g.,pneumatic, vacuum, hydraulic, electromechanical motors, drive shafts,etc. If a mechanism such as a flexible drive shaft were utilized, thepower for actuating the segments would preferably be developed by agenerator located at a distance from the segments, i.e., outside of apatient during use, and in electrical and mechanical communication withthe drive shaft. Alternatively, segments could be actuated by push-pullwires or tendons, e.g. Bowden cables, that bend segments by distributingforce across a segment, as described in “Tendon-Driven Endoscope andMethods of Insertion” filed Aug. 27, 2002 (attorney docket number514812000125), which is incorporated in its entirety by reference.

[0020] A proximal portion comprises the rest of the endoscope andpreferably a majority of the overall length of the device. The proximalportion is preferably a flexible tubing member that may conform to aninfinite variety of shapes. It may also be covered by a polymericcovering optionally extendable over the controllable portion and thesteerable distal portion as well to provide a smooth transition betweenthe controllable segments and the flexible tubing of the proximalportion. The controllable portion may be optionally omitted from theendoscope. A more detailed description on the construction and operationof the segments may be found in U.S. patent application Ser. No.09/969,927 entitled “Steerable Segmented Endoscope and Method ofInsertion” filed Oct. 2, 2001, which has been incorporated by referencein its entirety.

[0021] A proximal handle may be attached to the proximal end of theproximal portion and may include imaging devices connected to thefiberoptic imaging bundle for direct viewing and/or for connection to avideo camera or a recording device. The handle may be connected to otherdevices, e.g., illumination sources and one or several luer lockfittings for connection to various instrument channels. The handle mayalso be connected to a steering control mechanism for controlling thesteerable distal portion. The handle may optionally have the steeringcontrol mechanism integrated directly into the handle, e.g., in the formof a joystick, conventional disk controller using dials or wheels, etc.An axial motion transducer may also be provided for measuring the axialmotion, i.e., the depth change, of the endoscope body as it is advancedand withdrawn. The axial motion transducer can be made in many possibleconfigurations. As the body of the endoscope slides through thetransducer, it may produce a signal indicative of the axial position ofthe endoscope body with respect to the fixed point of reference. Thetransducer may use various methods for measuring the axial position ofthe endoscope body.

[0022] The guide is generally used to impart a desired curvatureinitially defined by the steerable portion and/or by the optionalcontrollable portion to the passive proximal portion when the endoscopeis advanced. If held or advanced into the steerable portion, the guideis preferably advanced to or near the distal tip of the portion. It isalso used to impart some column strength to the proximal portion inorder to maintain its shape and to prevent any buckling when axiallyloaded. Preferably, the guide is slidably disposed within the length ofthe endoscope body and may freely slide entirely through the passiveproximal portion, through the controllable portion, and the steerabledistal portion. The extent to which the guide may traverse through theendoscope body may be varied and adjusted according to the application,as described above. Furthermore, the proximal end of the guide may berouted through a separate channel to a guide controller which may beused to control the advancement and/or withdrawal of the guide and whichmay also be used to selectively control the rigidity of the guide ascontrolled by the physician.

[0023] The structure of the guide may be varied according to the desiredapplication. The following descriptions of the guide are presented aspossible variations and are not intended to be limiting in theirstructure. For instance, the guide may be comprised of two coaxiallypositioned tubes separated by a gap. Once the guide has been placed andhas assumed the desirable shape or curve, a vacuum force may be appliedto draw out the air within the gap, thereby radially deforming one orboth tubes such that they come into contact with one another and locktheir relative positions.

[0024] Another variation on the guide is one which is rigidizable by atensioning member. Such a guide may be comprised of a series ofindividual segments which are rotatably interlocked with one another inseries. Each segment may further define a common channel through which atensioning member may be positioned while being held between a proximaland a distal segment. During use, the tensioning member may be slackenedor loosened enough such that the guide becomes flexible enough to assumea shape or curve defined by the endoscope. When the guide is desirablysituated and has assumed a desired shape, the tensioning member may thenbe tensioned, thereby drawing each segment tightly against one anotherto hold the desired shape.

[0025] Another variation may use a guide which is comprised ofinterlocking ball-and-socket type joints which are gasketed at theirinterfaces. Such a design may utilize a vacuum pump to selectivelytighten and relax the individual segments against one another. Othervariations may include alternating cupped segments and ball segments, aseries of collinear sleeve-hemisphere segments, as well as other designswhich may interfit with one another in series. Such a guide may betightened and relaxed either by tensioning members or vacuum forces.

[0026] A further variation on the guide is a coaxially alignedstiffening member. This assembly may include a first subassemblycomprising a number of collinearly nested segments which may be held bya tensioning member passing through each segment. The first subassemblymay be rigidized from a flexible or flaccid state by pulling on thistensioning member. A second subassembly may comprise a number of annularsegments also collinearly held relative to one another with one or moretensioning members passing through each annular segment. The secondsubassembly preferably defines a central area in which the first nestedsubassembly may be situated coaxially within the second subassembly. Thefirst subassembly is preferably slidably disposed relative to the secondsubassembly thereby allowing each subassembly to be alternately advancedin a flexible state and alternately rigidized to allow the othersubassembly to be advanced. This design presents a small cross-sectionrelative to the endoscope or device through which it may be advanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 shows a representation of a conventional endoscope in use.

[0028]FIG. 2A shows a variation of an endoscopic device of the presentinvention.

[0029]FIGS. 2B and 2C show side sectional views of another variation ofthe present invention.

[0030]FIG. 3A shows a side view of an endoscopic device variation withthe outer layers removed to reveal a guiding apparatus disposed within.

[0031]FIGS. 3B and 3C show cross-sectional views of various examples forobstructing the guide lumen of the endoscope.

[0032]FIGS. 4A to 4C show cross-sectional views of various examples ofguiding apparatus which may be used to guide an endoscope.

[0033]FIGS. 5A and 5B show the cross-sectioned end and side views,respectively, of a guiding apparatus with a vacuum-actuated rigidizingvariation.

[0034]FIGS. 6A and 6B show the cross-sectioned end and side views,respectively, of a guiding apparatus with a tensioning or pre-tensionedelement for rigidizing the guide.

[0035]FIGS. 7A and 7B show the cross-sectioned end and side views,respectively, of a guiding apparatus with a segmented vacuum-actuatedrigidizing variation.

[0036]FIGS. 8A and 8B show the cross-sectioned end and side views,respectively, of a guiding apparatus with interconnecting jointedsegments for rigidizing the guide.

[0037]FIGS. 9A to 9C show end, side, and cross-sectioned views,respectively, of another variation on the guiding apparatus.

[0038]FIG. 10 shows the cross-sectioned side view of another variationon the guiding apparatus having alternating bead and sleeve segments.

[0039]FIG. 11A shows a side view of a nested guiding apparatus which ispart of a coaxial stiffening assembly.

[0040]FIG. 11B shows a side view of an annular guiding apparatus whichis also part of the coaxial stiffening assembly.

[0041]FIG. 11C shows the combination of the guides from FIGS. 11A and11B.

[0042]FIGS. 12A and 12B illustrate a representative example of advancingthe endoscope along a tortuous pathway using a single rigidizing step.

[0043]FIGS. 13A to 13H illustrate a representative example of advancingan endoscope through a patient's colon using a guiding apparatus toassist in advancing the endoscope.

[0044]FIGS. 14A and 14B show a variation on the withdrawal of theendoscope with or without the guiding apparatus for the selectivetreatment of sites along the patient's colon.

[0045]FIGS. 15A to 15C illustrate a representative example of advancingan endoscope through a tortuous path using the coaxial guiding apparatusshown in FIGS. 11A to 11C.

[0046]FIGS. 16A to 16E illustrate another variation of advancing anendoscope through a tortuous path using multiple guiding apparatuses.

DETAILED DESCRIPTION OF THE INVENTION

[0047]FIG. 1 shows a prior art colonoscope 10 being employed for acolonoscopic examination of a patient's colon C. The colonoscope 10 hasa proximal handle 16 and an elongate body 12 with a steerable distalportion 14. The body 12 of the colonoscope 10 has been lubricated andinserted into the colon C via the patient's anus A. Utilizing thesteerable distal portion 14 for guidance, the body 12 of the colonoscope10 has been maneuvered through several turns in the patient's colon C tothe ascending colon G. Typically, this involves a considerable amount ofmanipulation by pushing, pulling and rotating the colonoscope 10 fromthe proximal end to advance it through the turns of the colon C. Afterthe steerable distal portion 14 has passed, the wall of the colon Cmaintains the curve in the flexible body 12 of the colonoscope 10 as itis advanced. Friction develops along the body 12 of the colonoscope 10as it is inserted, particularly at each turn in the colon C. Because ofthe friction, when the user attempts to advance the colonoscope 10, thebody 12′ tends to move outward at each curve, pushing against the wallof the colon C, which exacerbates the problem by increasing the frictionand making it more difficult to advance the colonoscope 10. On the otherhand, when the colonoscope 10 is withdrawn, the body 12″ tends to moveinward at each curve taking up the slack that developed when thecolonoscope 10 was advanced. When the patient's colon C is extremelytortuous, the distal end of the body 12 becomes unresponsive to theuser's manipulations, and eventually it may become impossible to advancethe colonoscope 10 any farther. In addition to the difficulty that itpresents to the user, tortuosity of the patient's colon also increasesthe risk of complications, such as intestinal perforation.

[0048]FIG. 2A shows a variation of the steerable endoscope 20 of thepresent invention. The endoscope 20 has an elongate body 21 with amanually or selectively steerable distal portion 24, an automaticallycontrolled portion 28, which may be optionally omitted from the device,a flexible and passively manipulated proximal portion 22, and anexternally controlled and manipulatable tracking rod or guide 36 whichmay be slidably positioned within the endoscope 20.

[0049] The selectively steerable distal portion 24 can be selectivelysteered or bent up to a full 180° bend in any direction 26, as shown inthe figure. A fiberoptic imaging bundle 40 and one or more illuminationfibers 42 may extend through the body 21 from the proximal portion 22 tothe distal portion 24. Alternatively, the endoscope 20 may be configuredas a video endoscope with a miniaturized video camera, such as a CCDcamera, positioned at the distal portion 24 of the endoscope body 21.The images from the video camera can be transmitted to a video monitorby a transmission cable or by wireless transmission where images may beviewed in real-time or recorded by a recording device onto analogrecording medium, e.g., magnetic tape, or digital recording medium,e.g., compact disc, digital tape, etc. Optionally, the body 21 of theendoscope 20 may include one or two access lumens 38 that may optionallybe used for illumination fibers for providing a light source,insufflation or irrigation, air and water channels, and vacuum channels.Generally, the body 21 of the endoscope 20 is highly flexible so that itis able to bend around small diameter curves without buckling or kinkingwhile maintaining the various channels intact. When configured for useas a colonoscope, the body 21 of the endoscope 20 may range typicallyfrom 135 to 185 cm in length and about 13-21 mm in diameter. Theendoscope 20 can be made in a variety of other sizes and configurationsfor other medical and industrial applications.

[0050] The optional controllable portion 28 is composed of at least onesegment 30, and preferably several segments 30, which may becontrollable via a computer and/or controller located at a distance fromthe endoscope 20. Each of the segments 30 preferably has an actuatormechanically connecting adjacent segments 30 to allow for the controlledmotion of the segments 30 in space. The actuators driving the segments30 may include a variety of different types of mechanisms, e.g.,pneumatic, hydraulic, electromechanical motors, “off board” powereddrive shafts, tendons, etc. A proximal portion 22 comprises the rest ofthe endoscope 20 and preferably a majority of the overall length of thedevice 20. Proximal portion 20 is preferably a flexible tubing memberwhich may conform to an infinite variety of shapes. It may also becovered by a polymeric covering 39 optionally extendable overcontrollable portion 28 and steerable distal portion 24 as well toprovide a smooth transition between the controllable segments 30 and theflexible tubing of proximal portion 22. The proximal portion 22 may bemade from a variety of materials such as thermoset and thermoplasticpolymers which are used for fabricating the tubing of conventionalendoscopes.

[0051] A proximal handle 32 may be attached to the proximal end of theproximal portion 22. The handle 32 may include an ocular 33 connected tothe fiberoptic imaging bundle 42 for direct viewing. The handle 32 mayotherwise have a connector for connection to a video camera, e.g., a CCDcamera, or a recording device. The handle 32 may be connected to anillumination source 43 by an illumination cable 44 that is connected toor continuous with the illumination fibers 42. One or several luer lockfittings 34 may be located on the handle 32 and connected to the variousinstrument channels.

[0052] The handle 32 is connected to an electronic motion controller 45by way of a controller cable 46. A steering control 47 may be connectedto the electronic motion controller 45 by way of a second cable 48 or itmay optionally be connected directly to the handle 32. Alternatively,the handle may have the steering control mechanism integrated directlyinto the handle, e.g., in the form of a joystick, conventional diskcontrollers such as dials or wheels, etc. The steering control 47 allowsthe user to selectively steer or bend the selectively steerable distalportion 26 of the body 21 in the desired direction. The steering control47 may be a joystick controller as shown, or other known steeringcontrol mechanism. The electronic motion controller 45 controls themotion of the automatically controlled proximal portion 28 of the body21. The electronic motion controller 45 may be implemented using amotion control program running on a microcomputer or using anapplication-specific motion controller. Alternatively, the electronicmotion controller 45 may be implemented using, e.g., a neural networkcontroller.

[0053] An axial motion transducer 49 may be provided for measuring theaxial motion, i.e., the depth change, of the endoscope body 21 as it isadvanced and withdrawn. The axial motion transducer 49 can be made inmany possible configurations. For example, the axial motion transducer49 in FIG. 2A is configured as a ring 49 that may surround the body 21of the endoscope 20. The axial motion transducer 49 is preferablyattached to a fixed point of reference, such as the surgical table orthe insertion point for the endoscope 20 on the patient's body. As thebody 21 of the endoscope 20 slides through the axial motion transducer49, it produces a signal indicative of the axial position of theendoscope body 21 with respect to the fixed point of reference and sendsa signal to the electronic motion controller 45 by telemetry or by acable. The axial motion transducer 49 may use optical, electronic ormechanical methods to measure the axial position of the endoscope body21.

[0054] Similarly, when the endoscope body 21 is withdrawn proximally,each time the endoscope body 21 is moved proximally by one unit, eachsection in the automatically controlled proximal portion 28 is signaledto assume the shape of the section that previously occupied the spacethat it is now in. The curve propagates distally along the length of theautomatically controlled proximal portion 28 of the endoscope body 21,and the shaped curve appears to be fixed in space, as the endoscope body21 withdraws proximally. Alternatively, the segments of controlledportion 28 could be made to become flaccid and the withdrawal would thenbe passive.

[0055] Whenever the endoscope body 21 is advanced or withdrawn, theaxial motion transducer 49 detects the change in position and theelectronic motion controller 45 propagates the selected curvesproximally or distally along the controllable portion 28 of theendoscope body 21 to maintain the curves in a spatially fixed position.The axial motion transducer 49 also allows for the incrementing of acurrent depth within the colon C by the measured change in depth. Thisallows the endoscope body 21 to be guided through tortuous curveswithout putting unnecessary force on the wall of the colon C. Asmentioned above, such a segmented body 30 within the controllableportion 28 may be actuated by a variety of methods. One method involvesthe use of electromechanical motors which may be individually mounted oneach segment 30 to move the segments 30 relative to one another. Eachsegment 30 preferably defines at least one lumen running through it toprovide an access channel through which wires, optical fibers, airand/or water channels, various endoscopic tools, or any variety ofdevices and wires may be routed through.

[0056] A more detailed description on the construction and operation ofthe segments may be found in U.S. patent application Ser. No. 09/969,927entitled “Steerable Segmented Endoscope and Method of Insertion” filedOct. 2, 2001, which has been incorporated by reference in its entirety.

[0057] The guide 36 is generally used to impart a desired curvatureinitially defined by the steerable distal portion 24 and/or by theoptional controllable portion 28 to the passive proximal portion 22 whenthe endoscope 20 is advanced. If the guide 36 is advanced into thesteerable distal portion 24, guide 36 is preferably advanced to or nearthe distal tip of the portion 24. The guide 36 may also be used partlyto impart some column strength to the proximal portion 22 in order tomaintain its shape and to prevent any buckling when axially loaded, suchas when the endoscope 20 is advanced through a patient's colon.Construction of an endoscope 20 with the use of the guide 36 not onlysimplifies the control systems involved but it also represents a costefficient device. Operation of the endoscope 20 with guide 36 will bediscussed in detail below.

[0058] Preferably, the guide 36 is slidably disposed within the lengthof the endoscope body 21 and may freely slide entirely through thepassive proximal portion 22, through the optional controllable portion28, if utilized in the endoscope, and the steerable distal portion 24.Guide 36 may also be withdrawn through the instrument to any locationwithin the body of endoscope 20. Moreover, guide 36 may be removedentirely from endoscope 20, if desired e.g., to accommodate additionalworking tools. In other words, there are preferably no constraints whichmay limit the travel of guide 36 within the body of endoscope 20.

[0059] Guide 36 may be advanced through proximal handle 32;alternatively, guide 36 may also be routed through a separate channel 37dedicated to the guide 36. Channel 37 is preferably attached toendoscope 20 near a proximal end of the instrument, such as a locationoff the proximal portion 22, and leads to a guide controller 41 whichmay be used to advance and/or withdraw guide 36 through endoscope 20.Guide controller 41 may also be used to selectively rigidize and relaxguide 36 during use within a patient. Having guide controller 41 andproximal handle 32 separated may allow for the ease of use for thephysician manipulating the endoscope 20. To aid in advancing guide 36through endoscope 20, a pulley mechanism may be affixed within thesteerable distal portion 24 through which a pull wire may extend over toconnect the distal end of the guide 36 to a location outside theendoscope 20 for manipulation by the physician.

[0060] To facilitate the movement of guide 36 through endoscope body 21,a lubricious covering or coating may be applied over at least a majorityof the length of guide 36 or onto the inner surface of the lumen throughwhich guide 36 traverse, or both. Such coverings may include variouspolymers and plastics, e.g., PTFE, etc., which may simply cover theguide 36 length or which may be heatshrunk, coated, or bonded onto guide36, depending upon the material used. The extent to which guide 36traverses through the endoscope body 21 may be varied and adjustedaccording to the application.

[0061]FIGS. 2B and 2C show sectional partial views of a variation of theendoscope that is capable of single-step use of the guide. In thesevariations, the axial length of the guide 51 is shorter than theinsertable length of the endoscope 23. The endoscope body 21 includes asteerable distal tip 24 and a proximal controllable region 28 that iscomprised of flexible segments 30. Approximately half of the length ofthe endoscope body may be composed of controllable segments 30, and theremaining proximal part of the endoscope is flexible passive portion 22.The length of the guide 51 is approximately half that of the endoscopebody 23. Although the guide 51 is freely slidable within lumen 50 of theendoscope 23 in the variation shown, the guide 51 may be preloadedthrough the distal end of the endoscope 23 before insertion into thebody. Alternatively, the guide 51 could be positioned as describedabove. The guide 51 can be rigidized and held in place by the tensioningwire 36. The combination of steerable distal tip 24, controllableproximal portion 28 and guide 51 in this variation of the inventionsimplifies the use of the rigidizable guide 51 because the guide 51 onlyhas to be rigidized and locked into position once.

[0062]FIG. 2C shows another, slightly magnified, sectional view of theendoscope of FIG. 2B. This view illustrates an optional suction device53, e.g., a negative pressure pump device, which may be fluidlyconnected to suction port 202 through suction tube 204. Suction device53 is preferably located externally of the patient during use. Becauseinsufflated air or gas may be trapped within regions of the colon due tothe sacculation and movement of the colon walls, the suction device 53may be used to facilitate removal of these gases as the endoscope isadvanced or withdrawn through the colon. The suction port 202 shown ispreferably located at some point proximal of distal end 24, e.g.,approximately one quarter of the length of the endoscope body 23. Thissuction port can be located virtually anywhere along the length of theendoscope, but it is preferably located such that it does not interferewith the insufflation process at or near the distal tip.

[0063]FIG. 3A shows an isometric view of a length of the endoscope 20,in this example part of the proximal portion 22, with a section of theendoscope body 20 removed for clarity. As seen, a representativeillustration of the guide 36 may be seen disposed within guide channelor lumen 50 within the proximal portion 22. Lumen 50 may be an existingworking channel, i.e., an access channel for other tools, or it may be adesignated channel for guide 36 depending upon the desired application.Guide 36 may be inserted within guide channel 50 through the endoscopehandle 32 and pushed proximally through the remainder of the device, asseen in FIG. 2A; or preferably, it may be pushed proximally or pulleddistally, as necessary, through a separate guide controller 41, asdiscussed above. Although guide 36 is shown in this variation as beingslidably disposed interiorly of endoscope body 20, it may also bedisposed exteriorly of the body 20 to slide along a guide rail orexterior channel in other variations.

[0064] If guide 36 is located within a dedicated channel, such as lumen50, the distal end of this channel is preferably closed or blocked atsome distal location, e.g., within steerable distal portion 24 or withinoptional controllable portion 28, to prevent the influx of bodily fluidswithin lumen 50. Because an enclosed lumen 50 would further preventcontact of bodily fluids with guide 36, the amount of cleaning orsterilization of guide 36 is reduced.

[0065] If lumen 50 were left as an open channel, additionalsterilization or cleaning and disinfecting of guide 36 and lumen 50 maybe necessary. Alternatively, lumen 50 may be left as an open channel butconfigured to have optional closing mechanisms, as shown in the examplesof FIGS. 3B and 3C, taken from FIG. 3A. FIG. 3B shows an end view of atrap or door 54 which is held within the body of the instrument andwhich may be rotated about a pivot 56 in the direction of the arrow toclose access to lumen 50. Trap 54 may be closed during insertion of theinstrument within a patient and then optionally opened to allow forworking tools to be inserted therethrough. FIG. 3C shows another examplewhere lumen 50 may be obstructed by an inflatable balloon 59 which mayselectively expand to completely obstruct the passageway. Balloon 59 maybe made of conventional materials and may be held within a compartmentor step 58 such that lumen 50 is unobstructed when balloon 59 isdeflated. These examples merely present variations and are not meant tolimit the scope of the invention. Alternative designs and variations areintended to be within the scope of the present invention.

[0066]FIGS. 4A to 4C show variations on possible cross-sections 4A-4A,4B-4B, and 4C-4C, respectively, taken from FIG. 3A. FIG. 4A shows asimplified cross-section 22′ of a guide 36 having a circular diameterslidably disposed within proximal portion 22. As seen, guide 36 may beslidably positioned within channel 50′, which may also be used as aworking channel upon removal of guide 36 during, e.g., a colonoscopyprocedure, for providing access for various instruments or tools to atreatment site. FIG. 4B shows another possible variation incross-section 22″ where guide 36 is positioned within channel 50″. Thevariation of the proximal portion in cross-section 22″ may include anumber of access lumens 52 optionally formed within the body of thedevice 20. These lumens 52 may run through the length of device 20 andmay be used for various applications, e.g., illumination fibers,laparoscopic tools, etc. Although three lumens 52 are shown in thefigure, any number of channels as practically possible may be utilizeddepending upon the application at hand. FIG. 4C shows another variationin cross-section 22′″. In this variation, guide 36′ may be formed into asemi-circular or elliptical shape to slide within a similarly shapedchannel 50′″. In this example, proximal portion 22′″ also includes aworking channel 52′ which may be shaped accordingly to fit within thebody 22′″ along with channel 50′″ to maintain a working channel withouthaving to remove guide 36′. In any of the above examples, the working orguide channels are preferably integral structures within the body ofendoscope 20. Having an integral structure eliminates the need for aseparate lumened structure, e.g., a separate sheath, through which guide36 or any other tools may be inserted. Another variation utilizingmultiple channels and multiple guides will be described in furtherdetail below. These variations are not intended to be limiting but aremerely presented as possible variations. Other structures and variationsthereof may be recognized by one of skill in the art and are intended tobe within the scope of the claims below.

[0067] The structure of the guide may be varied according to the desiredapplication. The following description on the guide is presented aspossible variations and are not intended to be limiting in theirstructure. FIGS. 5A and 5B show cross-sectioned end and side views,respectively, of a guiding apparatus variation which is rigidizable by avacuum force applied within the guide. It is preferable that the guideis selectively rigidizable, i.e., when the guide assumes a shape orcurve in a flexible state, the guide may be rigidized to hold that shapeor curve for a predetermined period of time. Although the endoscopestructure of the present invention may utilize a guide which remains ina relatively flexible shape, it is preferable to have the guide beselectively rigidizable.

[0068] Guide 60 may be comprised of two coaxially positioned tubes,outer tube 62 and inner tube 64, which are separated by a gap 66 betweenthe two tubes. Inner tube 64 may define an access lumen 68 throughoutthe length of the tube to provide a channel for additional tools orother access devices. Both tubes 62, 64 are preferably flexible enoughto be bent over a wide range of angles and may be made from a variety ofmaterials such as polymers and plastics. They are also preferablyflexible enough such that either the outer tube 62, inner tube 64, orboth tubes are radially deformable. Once guide 60 has been placed andhas assumed the desirable shape or curve, a vacuum force may be appliedto draw out the air within gap 66. This vacuum force may radially deforminner tube 64 and bring it into contact with the inner surface of outertube 62 if inner tube 64 is made to be relatively more flexible thanouter tube 62. Alternatively, if outer tube 62 is made to be relativelymore flexible than inner tube 64, outer tube 62 may be brought intocontact with the outer surface of inner tube 64.

[0069] In another variation, tubes 62, 64 may both be made to beflexible such that they are drawn towards one another. In yet anothervariation, which may be less preferable, a positive force of airpressure or a liquid, e.g., water or saline, may be pumped into accesslumen 68. The positive pressure from the gas or liquid may force thewalls of inner tube 64 radially into contact with the inner surface ofouter tube 62. In any of these variations, contact between the twotubular surfaces will lock the tubes 62, 64 together by frictional forceand make them less flexible. An elastomeric outer covering 69, orsimilar material, may optionally be placed upon the outer surface ofouter tube 62 to provide a lubricious surface to facilitate the movementof guide 60 within the endoscopic device. An example of a device similarto guide 60 is discussed in further detail in U.S. Pat. No. 5,337,733,which has been incorporated herein by reference in its entirety.

[0070] Another variation on the guide is shown in FIGS. 6A and 6B whichshow cross-sectioned end and side views, respectively, of a guidingapparatus variation 70 which is rigidizable by a tensioning member 76.Tensioned guide 70 is shown comprised of a series of individual segments72 which are rotatably interlocked with one another in series. Eachsegment 72 may contact an adjoining segment 72 along a contacting lip78. Each segment 72 may further define a channel therethrough which,collectively along with the other segments 72, form a common channel 74throughout a majority of the length of guide 70. Segments 72 may becomprised of a variety of materials suitable for sustaining compressionforces, e.g., stainless steel, thermoplastic polymers, plastics, etc.

[0071] Proximal and distal segments of guide 70 may hold respective endsof, tensioning member 76, which is preferably disposed within commonchannel 74 through guide 70. Tensioning member 76 may be connected to atensioning housing located externally of a patient. During use when theguide is advanced distally through an endoscope of the presentinvention, tensioning member 76 is preferably slackened or loosenedenough such that guide 70 is flexible enough to assume a shape or curvedefined by the endoscope. When guide 70 is desirably situated and hasassumed a desired shape, tensioning member 76 may be tensioned. Thistightening or tensioning of member 76 will draw each segment 72 tightlyagainst one another along each respective contacting lip 78 such thatthe guide 70 becomes rigid in assuming the desired shape. A lubriciouscovering, e.g., elastomers, etc., may be optionally placed over at leasta majority of guide 70 to facilitate movement of the guide 70 relativeto the endoscopic device. A similar concept and design is discussed infurther detail in U.S. Pat. No. 5,624,381, which has been incorporatedherein by reference in its entirety.

[0072]FIGS. 7A and 7B show cross-sectioned end and side views,respectively, of a guiding apparatus variation 80 which is rigidizableby a vacuum force which interlocks individual segments 82. Each segment82 may be adjoined with adjacent segments by interlockingball-and-socket type joints which are preferably gasketed at theinterfaces 86 of each connection. Within each segment 82, with theexception of the distal segment, may be defined a channel which isnarrowed at one end and flared at the opposite end. Collectively whenthe segments 82 are adjoined into the structure of guide 80, each of theindividual channels form a common channel 84 which extends through atleast a majority of the segments 82 along the length of guide 80. At theproximal end of guide 80 a vacuum pump, which is preferably locatedexternally of the patient, is fluidly connected to common channel 84. Inuse, once guide 80 is manipulated in its flexible state within theendoscope to assume the desired shape or curve, ambient pressure mayexist within common channel 84. When the rigid shape of guide 80 isdesired, the pump may then be used to create a negative pressure withincommon channel 84 and this negative pressure draws each segment 82 intotight contact with one another to maintain the desired shape. When thevacuum force is released, each segment 82 would also be released andwould thereby allow the guide 80 to be in its flexible state foradvancement or withdrawal. Guide 80 may further be surrounded by anelastomeric or lubricious covering to aid in the advancement orwithdrawal of the guide 80 within the endoscopic device.

[0073]FIGS. 8A and 8B show cross-sectioned end and side views,respectively, of yet another guiding apparatus variation 90 which isoptionally rigidizable by either a vacuum force or a tensioning memberwhich interlocks individual segments 92. Segment 92 may be in the formof a segmented design with two opposed cups having a common channel 94defined therethrough. Between each segment 92 are ball segments 96 whichinterfits along a contact rim or area 97 within each adjacent segment92. Ball segments 96 preferably contact adjacent cupped segments 96within receiving channels 98 defined in each cup. When manipulated inits flexible state, guide 90 may be advanced or withdrawn or made toassume a desired shape or curve. When guide 90 is to be placed into itsrigidized shape, a vacuum force or tensioning member 99 may be utilizedin the guide 90 in similar manners as described above. Moreover, guide90 may similarly be surrounded by an elastomeric or lubricious coveringto aid in the advancement and withdrawal of the guide 90.

[0074]FIGS. 9A and 9B show representative end and side views,respectively, of another guiding apparatus variation 100. This variation100 comprises individual segments 102 having a uniform sleeve section104 in combination with an integrated curved or hemispherical section106. Each segment 102 is collinearly aligned with one another with thesleeve section 104 receiving the curved section 106 of an adjacentsegment 102, as shown in FIG. 9C, which is the cross-section of guide100 from FIG. 9B. The adjacent segments 102 may rotate relative to oneanother over the sleeve-hemisphere interface while maintaining a commonchannel 108 through the guide 100. A tensioning member 110 may passthrough channel 108 along the length of guide 100 for compressing theindividual segments 102 against one another when the entire guide 100 isrigidized.

[0075]FIG. 10 shows the cross-section of another variation 120 of therigidizable guide apparatus. Representative segments are showncomprising spherical bead segments 122 alternating with sleeve segments124. Each of the bead and sleeve segments 122, 124, respectively, mayhave a channel defined therethrough which allows for a tensioning member126 to be run through the length of guide 120. The alternating segmentsallow for the rotation of the adjacent segments while the tensioningmember 126 allows for the compression of the segments against oneanother when the guide 120 is to be rigidized in much the same manner asdescribed above.

[0076] An alternative variation on the rigidizable guide is illustratedin FIGS. 11A to 11C, which show a stiffening assembly having separaterigidizable coaxially positioned guides. FIG. 11A shows a representativenumber of nested segments 132 in nested stiffening assembly 130. Eachnested segment 132 may be in a number of different configurations, e.g.,ball socket joints, stacked ring-like segments, etc., with a tensioningmember 134 passing through each of the segments 132. For use with nestedassembly 130, an annular stiffening assembly 140 may be seen in FIG.11B. Annular assembly 140, of which only a few representative segmentsare shown, are comprised in this variation of annular segments 142 whichmay be stacked or aligned one atop each other. At least one tensioningmember 144, and preferably at least two, may be passed through each ofthe annular segments 142. A central area 146 is defined in each annularsegment 142 such that nested stiffening assembly 130 may be slidinglyplaced within the central area 146 defined by the annular stiffeningassembly 140. FIG. 11C shows the stiffening assembly 130 slidinglypositioned within annular stiffening assembly 140 to form the coaxiallyaligned stiffening assembly 150. Use of coaxial assembly 150 will bedescribed in further detail below.

[0077]FIGS. 12A and 12B illustrate a variation of the endoscopeadvancing through a tortuous path, using an endoscope similar to thevariation of FIG. 2B. FIG. 12A shows a pathway with multiple turns 210,resembling a length of the colon. The distal half of the device 212comprises a steerable distal portion 24 and a controllable proximalportion 28. The guide 51 is slidably held within a lumen within theendoscope in the relaxed state. As the device 212 is advanced into thepathway 210, the user steers the distal tip 24, and the controllablesegments 30 follow the curve selected by the user, navigating the chosenpathway. While in the relaxed state, the guide 51 may passively assumethe shape taken by the distal portion 24 and the controllable proximalportion 28 as they are steered along the path. Usually, the user mayrigidize and/or “lock” the guide 51 to assume the curve of the selectedpathway before the controllable proximal portion 28 has advanced beyondthe first curve 220. After being stiffened and locked into position, theendoscope can continue moving distally while still maintaining theselected pathway, since the passive flexible proximal region 22 of theendoscope slides over the rigid guide 51 and conforms to its shape, asshown in FIG. 12B.

[0078] After rigidizing the guide, the user can continue to steer thedistal end 24 as it is advanced, and the curves of the selected pathwayare propagated proximally down the controllable segments 30 as theendoscope moves forward. This variation of the device is capable ofconforming to a selected pathway over the entire length of theendoscope, despite having a shorter guide 51 and controllable portion28, since the combined length of the guide 51 and the controllableportion is preferably equal to the length of the endoscope.

[0079] In operation, any of the guiding apparatus as described above orone recognized by a person of skill in the art to be suitable for suchuse as described herein may be utilized. FIGS. 13A to 13H illustrate arepresentative method of advancing a colonscopic device 20 as describedherein with a representative guide 36 for advancement into a patient'scolon C. As seen in FIG. 13A, the steerable distal portion 24 ofcolonoscope 20 may be first advanced into the patient's rectum via anusA. The device 20 may be simply advanced, either manually orautomatically by a motor, until the first curvature is reached oralternatively until the segments of controllable portion 28 are withincolon C. At this point, the steerable distal portion 24 may be activelycontrolled by the physician or surgeon to attain an optimal curvature orshape for advancement of device 20. The optimal curvature or shape isconsidered to be the path which presents the least amount of contact orinterference from the walls of colon C. If the optional controllableportion 28 is used with the colonoscopic device 20, once the advancementposition 160 has been determined, the device 20 may be advanced furtherinto the sigmoid colon S such that the automatically controlled segmentsof controllable portion 28 follow the distal portion 24 whiletransmitting the optimal curvature or shape proximally down theremaining segments of controllable portion 28.

[0080] Alternatively, once steerable distal portion 24 has been steeredor positioned for advancement 160, guide 36 may be advanced distally inits flexible state along or within device 20 until it reaches a distalposition, i.e., some point distal of the flexible proximal portion 22and preferably to the distal end of the device 20, as shown in FIG. 13B.Preferably, guide 36 is advanced to the distal end of steerable distalportion 24 or to the distal end of the optional controllable portion 28,if utilized, or to some point therebetween. Guide 36 may be advanced toany distal position as long as a portion of guide 36 attains the optimalcurvature or shape. Prior to advancing the device 20 over guide 36, theguide 36 may be left in its flexible state or it may be optionallyrigidized, as discussed above. If left in its flexible state, guide 36will still provide desirable column strength to the device 20 as it isadvanced through colon C over the guide 36. It is preferable, however,that guide 36 is rigidized once it has attained and conformed to thecurvature. As the position of guide 36 is preferably rigidized andmaintained, the device 20 may then be advanced over the guide 20 in amonorail or “piggy-back” fashion so that the flexible proximal portion22 follows the curve held by guide 36 until the device 20 reaches thenext point of curvature. The following description discusses the use ofthe optional controllable portion 28; however, this portion 28 may beomitted from the device 20.

[0081] As shown from FIGS. 13B to 13C, the curve is maintained by guide36 until the steerable distal portion 24 has been advanced to thejuncture between the sigmoid colon S and the descending colon D. At thispoint, the distal portion 24 may be actively steered by the physicianusing a variety of visualization techniques, e.g., steering via anoptional imaging bundle 40 located at the distal end of the device 20.Once the optimal curve or shape has been determined, the device 20 maybe advanced to position 160. As the device is moved distally, if thecontrollable portion 28 is utilized, portion 28 will automaticallyfollow the path set by the distal portion while the flexible proximalportion follows the device 20 along the curvature defined by the guide36. Otherwise, if controllable portion 28 is omitted, guide 36 will haveits curvature defined solely by steerable distal portion 24. Once thejunction between the sigmoid colon S and descending colon D has beentraversed by the steerable distal portion 24 and the optionalcontrollable portion 28, the guide may then be relaxed and advanceddistally along the device 20 in its flexible state until it reaches thedistal position in the device 20. As the guide 36 is advanced, it willattain and conform to a new curvature defined by the steerable distalportion 24 and/or the controllable portion 28, as shown in FIG. 13D.

[0082] Having attained a new curvature, guide 36 may again be rigidizedto maintain this shape. While the guide 36 maintains this shape, thedevice 20 may be advanced further distally along the descending colon Dwith the help of the rigidized guide 36 in the piggy-back mannerdescribed above to define the path for the flexible proximal portion 22and to prevent excessive contact with the walls of colon C. As shown inFIG. 13E, the device 20 has been advanced past the left (splenic)flexure F₁ in the manner described above until the optional controllableportion 28 has attained the optimal curvature. The guide 36 may berelaxed again and advanced further distally in its flexible state, asshown from FIGS. 13E to 13F.

[0083] After guide 36 has assumed the desired curvature defined by thedistal portion 24 and/or controllable portion 28, as shown in FIG. 13F,it may again be rigidized and the device 20 may then be advanced throughthe transverse colon T and around the right (hepatic) flexure F_(r) inmuch the same manner as described above and as shown in FIG. 13G. Oncethe distal portion 24 and the optional controllable portion 28 hascontrollably negotiated past the right (hepatic) flexure F_(r), theposition of guide 20 may again be maintained while guide 36 is relaxedonce again and advanced distally to assume the new curvature defined bydistal portion 24 and/or controllable portion 28, as shown in FIG. 13H.After guide 36 is optionally rigidized again, device 20 may be advanced160 completely within the ascending colon G towards the cecum E for acomplete examination of the colon C with minimal complication andeffort.

[0084] While the device 20 is advanced through the colon C, thephysician or surgeon may stop the advancement to examine various areasalong the colon wall using, e.g., the imaging bundle 40. During suchexaminations, the guide 36 may be temporarily withdrawn manually orautomatically from the device 20 to allow for the insertion of othertools through the guide channel 50. After a procedure has been completedon the colon wall, the tool may be withdrawn from guide channel 50 andguide 36 may be reintroduced into the device 20 so that the device mayoptionally be advanced once again into colon C.

[0085] To withdraw device 20 from within the colon C, the procedureabove may be reversed, as shown in FIG. 14A, such that the withdrawal162 minimally contacts the walls of colon C. Alternatively, guide 36 maysimply be removed from device 20, as shown in FIG. 14B, while leavingdevice 20 within colon C. The device 20 may simply be withdrawn bypulling the proximal portion 22 to remove the device 20. This method mayrub or contact the device 20 upon the walls of colon C, but anyimpingement would be minimal.

[0086] An alternative method of advancing an endoscope through atortuous path may be seen in FIGS. 15A to 15C by using the rigidizableguide assembly 150 seen from FIG. 11C. FIG. 15A shows a pathway to benegotiated by endoscopic device 172. The pathway may represent a portionof colon 170. As device 172 is desirably steered to assume a curve,nested stiffening assembly 130 may be advanced distally within device172 to distal end 174 while in a relaxed state. Alternatively, nestedassembly 130 may be advanced in the flexible, relaxed state along withthe distal end 174.

[0087] Once the curve has been selected, nested assembly 130 may bestiffened to maintain its shape. At this point, annular stiffeningassembly 140 may be advanced over nested assembly 130 towards distal end174. Once assembly 140 has assumed the curve defined by assembly 130,annular assembly 140 may then be rigidized and nested assembly 130 maybe relaxed into its flexible state, as shown in FIG. 15B. Then thedistal end 174 may be further advanced with or without assembly 130while being pushed along the curve defined by rigidized annular assembly140, as shown in FIG. 15C. Once distal end 174 of device 172 hasnegotiated the curve, nested assembly 130, after being advanced todistal end 174, may then be rigidized again and annular assembly 140 maybe relaxed and advanced again over assembly 130 and so on until thedesired treatment location has been reached within the body.

[0088] Another alternative variation on advancing an endoscope through atortuous path may be seen in FIGS. 16A to 16E. This variation usesmultiple guides which may be alternately rigidized while being advanceddistally along the path. FIG. 16A shows a portion of the curved pathwayin colon 170 with endoscope 180 being advanced therethrough. Multipleguides may be used in this variation, but preferably two guides areutilized, as described below. Any one of the rigidizable guidevariations discussed herein may be used solely or in combination withdifferent types of guides in the same device 180. Each guide may beadvanced within its own lumen defined within the endoscope, or they mayalso share a common dedicated lumen.

[0089] As device 180 approaches a curvature of colon 170, first guide184 may be advanced towards the steerable distal end 182. While beingadvanced, first guide 184 is in a relaxed and flexible state allowing itto conform to the shape defined by the distal end 182. Having beenadvanced to distal end 182, as shown in FIG. 16B, first guide 184 isrigidized to maintain the shape defined by the steerable distal end 182.Device 180 may then be advanced further distally into colon 170 whileriding over rigidized first guide 184.

[0090] After device 180 has been further advanced to a new position,second guide 186 may also be advanced distally in its relaxed statethrough device 180 up to the distal end 182 while first guide 184 ispreferably still rigidized, as shown in FIG. 16C. As second guide 186advances, it may conform to a new shape defined by device 180. Secondguide 186 may then be rigidized to hold its shape. First guide 184 maybe relaxed but its rigid shape is preferably also maintained while thedistal end 182 of device 180 is further advanced distally through colon170, as shown in FIG. 16D.

[0091] After device 180 has been advanced distally, first guide 184 maybe relaxed and advanced through device 180 up to distal end 182 whilethe rigidity of second guide 186 is maintained, as shown in FIG. 16E.Second guide 186 may be relaxed and then advanced in its flexible statedistally through device 180 and so on. This process may be repeated asdevice 180 is required to negotiate arbitrarily tortuous paths.

[0092] Although the endoscope of the present invention has beendescribed for use as a colonoscope, the endoscope can be configured fora number of other medical and industrial applications. In addition, thepresent invention can also be configured as a catheter, cannula,surgical instrument or introducer sheath that uses the principles of theinvention for navigating through tortuous body channels. The presentinvention may also be used for industrial applications such asinspection and exploratory applications within tortuous regions, e.g.,machinery, pipes, etc.

[0093] In a variation of the method that is particularly applicable tolaparoscopy or thoracoscopy procedures, the steerable endoscope can beselectively maneuvered along a desired path around and between organs ina patient's body cavity. The distal end of the endoscope may be insertedinto the patient's body cavity through a natural opening, through asurgical incision or through a surgical cannula, introducer, or trocar.The selectively steerable distal portion can be used to explore andexamine the patient's body cavity and to select a path around andbetween the patient's organs. The electronic motion controller inconjunction with the tracking rod can be used to control theautomatically controlled proximal portion to follow the selected pathand allow the rest of the body to follow the tracking rod and, ifnecessary, to return to a desired location using the three-dimensionalmodel in the electronic memory of the electronic motion controller.Modification of the above-described assemblies and methods for carryingout the invention, and variations of aspects of the invention that areobvious to those of skill in the art are intended to be within the scopeof the claims.

We claim:
 1. A method of advancing an instrument along an arbitrarypath, comprising: selectively steering a distal portion of theinstrument to assume a selected shape along an arbitrary path such thata portion of an elongate guide conforms to and assumes the selectedshape; and maintaining a position of said guide while advancing saidinstrument along said guide such that a proximal portion of saidinstrument assumes the selected shape defined by said guide, whereinsaid instrument is freely slidable along said guide such that advancingsaid instrument along said guide is unconstrained.
 2. The method ofclaim 1 wherein prior to maintaining a position of said guide, furthercomprising advancing said instrument distally while configuring acontrollable portion of said instrument to assume the selected shape ofsaid distal portion, wherein said controllable portion is proximal tosaid distal portion.
 3. The method of claim 1 wherein maintaining theposition of said guide comprises rigidizing said guide such that saidguide rigidly assumes a position of the selected shape.
 4. The method ofclaim 3 wherein rigidizing said guide comprises applying tension to atensioning member disposed within said guide such that a plurality ofadjacent segments comprising said guide are compressed.
 5. The method ofclaim 3 wherein rigidizing said guide comprises applying a vacuum forcewithin a lumen defined within said guide such that a plurality ofadjacent segments comprising said guide are compressed.
 6. The method ofclaim 1 further comprising withdrawing said guide from said instrument.7. The method of claim 1 wherein said guide is slidably located withinsaid instrument through a lumen defined within the instrument.
 8. Themethod of claim 7 wherein prior to steering said distal portion of saidinstrument, the distal end of said guide is disposed within the distalend of said lumen.
 9. A method of advancing an instrument along anarbitrary path, comprising: providing an instrument having a proximalend, a controllable proximal portion, and a selectively steerable distalportion, and further providing an elongate guide having a distal portionpositioned substantially adjacent to said distal portion of saidinstrument; selectively steering said distal portion of said instrumentto assume a selected shape along a desired path; advancing saidinstrument distally along said desired path while controlling saidcontrollable proximal portion to assume the selected shape of saiddistal portion such that said guide also assumes substantially theselected shape; and maintaining a position of said guide while advancingsaid instrument along said guide such that a proximal portion of saidinstrument assumes the selected shape defined by said guide, whereinsaid instrument is freely slidable along said guide such that advancingsaid instrument along the guide is unconstrained.
 10. The method ofclaim 9 wherein maintaining the position of said guide comprisesrigidizing said guide such that said guide rigidly assumes a position ofthe selected shape.
 11. The method of claim 10 wherein rigidizing saidguide comprises applying tension to a tensioning member disposed withinsaid guide such that a plurality of adjacent segments comprising saidguide are compressed.
 12. The method of claim 10 wherein rigidizing saidguide comprises applying a vacuum force within a lumen defined withinsaid guide such that a plurality of adjacent segments comprising saidguide are compressed.
 13. The method of claim 9 further comprisingwithdrawing said guide from the instrument.
 14. An apparatus forinsertion into a body cavity, comprising: an elongate body having aselectively steerable distal portion adapted to assume a selected shapealong an arbitrary path, a controllable proximal portion locatedproximal to said steerable distal portion, adapted to propagate theselected shape, and a flexible proximal portion proximal to saidcontrollable proximal portion; and an elongate guide having an axiallength that is less than an axial length of said elongate body, whereinsaid guide is configured to conform to and selectively maintain theselected shape assumed by said steerable distal portion; wherein saidflexible proximal portion of said elongate body is adapted to conform toa selected shape maintained by said guide.
 15. The apparatus of claim 14wherein said axial length of said guide is approximately equal to acombined length of said controllable proximal portion and said steerabledistal portion.
 16. The apparatus of claim 14 wherein said elongate bodydefines a lumen therethrough.
 17. The apparatus of claim 16 wherein saidguide is slidably disposed within said lumen.
 18. The apparatus of claim14 wherein said selectively steerable distal portion is controllable viaa control located externally of the body cavity.
 19. The apparatus ofclaim 14 wherein said a length of said proximal controllable portion isapproximately equal to half the length of said elongate body.
 20. Theapparatus of claim 14 wherein said proximal controllable portioncomprises a plurality of pivotally connected segments.
 21. The apparatusof claim 20 wherein each of said segments comprises an actuator forpropagating the selected shape along said proximal controllable portion.22. The apparatus of claim 21 wherein said actuator comprises a type ofmotor selected from the group consisting of pneumatic, hydraulic,electromechanical motors and drive shafts.
 23. The apparatus of claim 21wherein said actuator comprises a tendon.
 24. The apparatus of claim 14wherein said guide is configured to assume the selected shape when theguide is in a flexible state and wherein said guide is furtherconfigured to maintain the selected shape when the guide is in arigidized state.
 25. The apparatus of claim 24 wherein said guide isconfigured to selectively rigidize along the length of said guide tomaintain the selected shape in the rigidized state.
 26. The apparatus ofclaim 24 wherein the proximal section of said guide is in communicationwith a guide controller for selectively rigidizing the guide along itslength.
 27. The apparatus of claim 24 wherein said guide comprises aplurality of adjacent segments each defining a channel therethrough suchthat a common channel is defined through the length of the guide. 28.The apparatus of claim 27 further comprising a tensioning memberdisposed within said common channel such that applying a force to saidtensioning member compresses said adjacent segments together.
 29. Theapparatus of claim 27 wherein said guide is configured to maintain aposition of said adjacent segments relative to each other upon applyinga vacuum force within said common channel.
 30. The apparatus of claim 14further comprising a suction device for withdrawing a gas from the bodycavity through the elongate body.
 31. The apparatus of claim 30 whereinthe suction device is in fluid communication with a suction port definedon an outer surface of said elongate body.
 32. The apparatus of claim 30wherein said suction device is controllable via a controller locatedexternally of the body cavity
 33. The apparatus of claim 30 wherein saidsuction device is configured to operate continuously.
 34. An apparatusfor inserting into a body cavity comprising: an elongate body having aproximal portion and a selectively steerable distal portion and defininga lumen therebetween, the steerable distal portion being configurable toassume a selected shape along an arbitrary path; a suction device forwithdrawing a gas from the body cavity and through the elongate body,wherein the suction device is in fluid communication with a suction portdefined on an outer surface of said elongate body; an elongate guidehaving a proximal section, a distal section, and a length therebetween,said guide being slidably disposed without constraint within said lumenfor selectively supporting said body, wherein said guide is configuredto conform to and selectively maintain the selected shape assumed bysaid steerable distal portion, and wherein said proximal portion of saidelongate body when advanced distally is configured to conform to theselected curve maintained by said guide.